The present invention deals with an implantable medical device. While the device could be utilized in the context of a variety of body spaces, and particularly in the context of a variety of septal defects, the present description, for the sake of brevity, will be focused primarily on the treatment of ventricular septal defects. Accordingly, the present invention deals with an implantable medical device for at least partially obstructing a ventricular septal defect.
A ventricular septal defect is characterized by incomplete closure (i.e., a hole) in the intraventricular septum, the heart muscle forming a wall between ventricles within the heart. The intraventricular septum is meant to prevent blood passing from one ventricle to the next. A septal defect can undesirably allow blood to flow from one ventricle to the other, forcing some heart chambers to pump extra blood. This increase in blood can potentially cause the heart to dilate, a weakening of the heart muscle, and pressures in the pulmonary arteries to increase (pulmonary hypertension). In addition, when the intraventricular septum is broken, an undesirable mixing of oxygen-depleted blood from the veins with oxygenated blood going to the arteries is a potential problem. In many instances, these consequences can be minimized or even avoided through a natural or treatment-based obstruction of the septal defect.
The size of ventricular septal defects is variable. Small-to-medium sized defects often close naturally and spontaneously. Many of the larger defects, however, require surgical treatment. If a substantial sized defect is not properly treated, then pressures in the pulmonary arteries may become very high and induce undesirable changes in the arteries themselves. Eventually, if the defect is not corrected, then conditions can deteriorate until even a successful closure of the defect will no longer improve the patient outcome.
Different implantable medical devices have been developed for obstructing ventricular septal defects. Intravascular devices, such as catheters and guide wires, have been used to deliver a variety of these devices to a specific location, such as within a particular ventricle, within a patient""s heart. A variety of simple and complex devices are known to be deliverable to a septal defect through a catheter.
One class of catheter-delivered devices designed for the treatment of septal defects are self-expanding defect obstructing devices. A rod-like element is typically connected to these devices and utilized to push the devices from the end of a delivery catheter into a location proximate a septal defect, thereby causing an expansion of the device as it leaves the catheter. The expanded devices are typically maneuvered relative the defect until a secured position, a position where the device will stay in place and cause an obstruction of blood flow through the defect, is located. When the expanding devices have been maneuvered to a secured position, they are typically detached from any catheter, guide wire, or rod-like element utilized for intravascular placement. The expanding devices are left in a location proximate the septal defect and are intended to obstruct blood flow through the defect.
Some implantable self-expanding defect obstructing devices include separate extending portions that expand on both sides of a septal defect and into both of the heart chambers that are connected by the defect. Other devices are balloon-actuated devices, wherein expansion occurs as a result of inflation of extending members. Still other devices include mechanically expanding extending members that collapse (i.e., during delivery through a catheter) and can be extended (i.e., in a location proximate a septal defect) utilizing a mechanically maneuverable frame. Other devices are constructed of shape-memory based material, allowing the device to be manipulated into a collapsed shape and inserted into a catheter. Upon being pushed out of the catheter, these devices regain their original shape (i.e., a shape convenient for obstructing a septal defect).
Designing an effective implantable medical device for the obstruction of a septal defect presents special challenges. Many self-expanding devices suffer from deployment problems (i.e., incomplete opening of extending members or an error in the functionality of the extending member deployment mechanics). Many lack the ability to be precisely and effectively positioned relative a septal defect. In many instances, the shape of known implantable devices fails to effectively accommodate the often complex shape of a septal defect. With most known devices, recovery of a deployed device is difficult if not impossible. Many known devices require highly complex manufacture processes.
One aspect of the present invention pertains to an implantable medical device for at least partially obstructing a septal defect. The implantable medical device includes an obstruction mechanism connected to a non-linear elongated tissue-puncturing end.
Another aspect of the present invention pertains to an implantable device, deliverable via a vascular catheter, of a size and overall flexibility to lodge in an area of tissue located proximate a septal defect, and suitable for at least partially obstructing the septal defect. The implantable device includes an elongated delivery member having a distal end. An obstruction mechanism is connected to a coil that includes a puncturing end. The obstruction mechanism includes a ring-shaped structure having an interior portion. A material covering substantially fills the interior portion of the ring-shaped structure. A connection between the distal end of the elongated delivery member and the obstruction mechanism enables the obstruction mechanism to be rotated.
Yet another aspect of the present invention pertains to a method for at least partially obstructing a septal defect in a heart by implanting a medical device. The method first includes the step of placing a distal end of a catheter in a location proximate the septal defect. Next, an elongated delivery member is utilized to push an obstruction device through the catheter until a puncturing member portion of the obstruction device extends from the distal end of the catheter. Then, with the puncturing member, an area of tissue proximate the septal defect is punctured. Next, the obstruction device is rotated such that a non-linear tissue engaging section of the obstruction device, which is connected to the puncturing member, becomes substantially embedded in the area of tissue proximate the septal defect. Finally, the catheter and elongated delivery member are removed from the heart.